Existing enteral nutritionals are supplied either as powders requiring mixing or as liquids contained in cans and bottles which require transfer to a secondary application container. The use of sterile aseptic packaging would allow these products to be supplied in a "ready to use" form. Furthermore, if the contents of these containers could be accessed in an aseptic manner, the contents would have a reduced susceptibility to spoilage during use and would require no refrigeration.
There are two separate and distinct problems which would normally prevent such aseptic access. The first problem is that the contents of the container could not be withdrawn without creating a partial vacuum in the container, unless the container were vented to the atmosphere. Because open venting would allow microbial invasion of the container, spoilage would result.
The other problem is that all low acid food processing is subject to a failure rate of about eight containers per one hundred thousand for microbiological reasons. Approximately five of these failures are due to bacteria which produce carbon dioxide that causes the container to swell and leak. Such failures are immediately apparent to any end user and would result in the container being discarded prior to use. However, the other three failures would be of the "flat sour" type. The bacteria which cause "flat sour" failures contaminate the contents of the container, but do not generate carbon dioxide. Thus, the spoilage is not readily apparent. The three characteristics associated with "flat sour" failures are off odors, curdling and increased acidity (the pH would be lowered from approximately 6.5 to about 4.8). Because feeding of such a spoiled product to a compromised patient might have catastrophic effects, all containers would normally be opened and then examined both visually and aromatically prior to use. Such inspection would prevent the nutritional from being transferred to the patient directly from the container.
In the past, pH indicators have been proposed for determining whether various types of food have spoiled (see, for instance, U.S. Pat. Nos. 2,626,855 and 3,067,015). However, none of these indicators is combined with an insertable dispensing device for dispensing the food after a determination has been made that the food is suitable for consumption.
Vented dispensing devices have also been proposed in the past (see, for instance, U.S. Pat. Nos. 1,615,873 and 2,409,343). However, none of these devices incorporates a spoilage indicator.